Considered “a gift from the Great Spirit that was dropped from the beak of a dove into the swamps,” Native Americans used the red berry to dye blankets and make pemmican, a food made of crushed berries, fat, and dried meat. They also used it as a medicine to extract poison from wounds.1
It wasn’t until 1647, however, that the word Craneberry (the original English word for cranberry) first appeared in a letter written by a Cape Cod missionary. Shortly after that, it became popular as a vitamin C supplement to prevent scurvy on sailing expeditions, and as a remedy for gallbladder disorders, gastric ailments, blood problems, and even cancer1—which is particularly interesting, since researchers only recently discovered that it is a potent anti-cancer agent.234
Preventive for UTIs—Urinary tract infections
Urinary tract infections (UTIs) result in approximately 7 million doctor visits and a million hospitalizations each year, adding up to $1.6 billion in medical expenditures in the U.S.5 A large percentage of individuals with spinal cord injuries suffer from UTIs. Men can also get a bladder infection, especially if they have an enlarged prostate. Women, however, are primarily affected. In fact, about 25% of all women in the U.S. have at least one UTI in their lifetime, with 20% having three or more a year.6
Antibiotics don’t always work, and to complicate matters, even if the antibiotic does work, it weakens the immune system, making it easier to get a subsequent infection. The good news is that cranberry extract can nip UTIs in the bud.
How do you get a UTI?
A urinary tract infection is a bacterial infection that causes painful urination and the feeling that your bladder is never completely empty. It can also cause fever and low back pain. According to researchers at the Washington University (WU) School of Medicine in St. Louis, a UTI starts when Escherichia coli (E. coli) (a microorganism that lives in the digestive tract and is found in the anal area) invade the bladder and penetrate a protective coating of the superficial cells that line the bladder. Once the E. coli is established in the bladder lining, the stage is set for infection.7
How does cranberry extract work?
Cranberry extract is an extract of the red acidic fruit of the shrubby viburnum of North America and Europe. It contains phytochemicals that include flavonol glycosides, anthocyanins, proanthocyanidins (condensed tannins), and organic and phenolic acids. But it is the proanthocyanidins that exhibit potent bacterial anti-adhesion activity.8 The proanthocyanidins found in cranberry differ from those found in other plants by their unique structures and very potent antibacterial activity. In the case of UTIs, these proanthocyanidins prevent E. coli from adhering to the urethra and bladder.9
Here’s how: The cell wall of E. coli bacteria has tiny finger-like projections that contain complex molecules called lectins on their surfaces. These lectins are the cellular glue that binds the bacteria to the bladder wall so they cannot be easily rinsed out by urination. But because proanthocyanidin molecules attach themselves to these lectins and fill up all of the bacterial anchoring sites, the bacteria can no longer stick to the bladder wall and are flushed away.
- In a study of 153 elderly women, those who drank 10 oz of commercial cranberry drink each day had less than half the risk of developing an infection and were more likely to clear an already present infection.10
- A study of 10 young women with recurrent bladder infections found that, compared with placebo, taking a capsule containing 400 mg of cranberry extract daily for three months significantly reduced new infections. Of the 21 bladder infections that arose, only six occurred among women taking Cranberry.11
- A year-long Canadian study of 150 sexually active women found that cranberry juice and tablets significantly decreased the number of patients experiencing at least 1 symptomatic UTI/year compared with placebo. The study also found that taking cranberry was much more cost effective than taking antibiotics.12
- In February 2004, France allowed food, drink, and dietary supplement manufacturers a “function use claim” to highlight the health benefits of products containing cranberry to consumers. In turn, this will permit the claim that the North American cranberry VM (Vaccinium macrocarpon) can ‘help reduce the adhesion of certain E. coli bacteria to the urinary tract walls.’
Helps individuals with spinal cord injuries
UTIs are very common in individuals with spinal cord injuries since many of them have an indwelling catheter. Cranberry extract has been very helpful among this population in treating infections that arise from bacteria sticking to the urethra and bladder wall.13
Cranberries may reduce brain cell damage associated with stroke
In laboratory studies using rat brain cells exposed to simulated stroke conditions, a concentrated cranberry extract reduced the death of brain cells by half in comparison to cells that did not receive the extract, said the scientists. The findings suggest that cranberries can aid recovery from stroke, particularly in its earliest stages in which the most severe damage occurs.
“This study shows that cranberries have the potential to protect against brain cell damage that occurs during a stroke event,” said Catherine Neto, an assistant professor at the University of Massachusetts, Dartmouth and a lead investigator in the study. “It may not stop a stroke from occurring initially, but it may reduce the severity of stroke,” she added. The research from the unpublished study was presented in September 2003 at an American Chemical Society meeting.
Helps prevent tooth decay
Inhibits the growth of cancer cells
Since a blood supply to malignant tumors is crucial to the growth of the cancer, researchers have made it a priority to discover anti-angiogenic therapies (ways to stop the blood supply to the tumor) in the battle to prevent and treat cancer. The recent studies showing that edible berries may have potent chemopreventive and anti-angiogenic properties are promising.
Researchers at the Department of Chemistry and Biochemistry, University of Massachusetts, Dartmouth have spent years studying the effect of cranberry’s active constituents on cancer cells. They found that when compared to other natural compounds, the compounds in cranberry are more successful at inhibiting the growth of tumor cells.16 They also found that as an antioxidant, cranberry is as potent, if not more potent, as vitamin E.17
A recent study at the Department of Physiology & Pharmacology, University of Western Ontario, Canada examined the effect of cranberry extract on mice that had been injected with human breast tumor cells. The cranberry extract decreased the growth and metastasis of the tumors. Further studies done on human tumor cell lines, including prostate, skin, brain, colon, lung, and breast, also indicated that cranberry extract inhibited the growth of the cancer cells.18 Cranberry extract and the extracts of 5 other berries (blueberry, bilberry, elderberry, raspberry, strawberry) were studied for their antioxidant and anti-angiogenic properties at the Laboratory of Molecular Medicine, Ohio State University. They were all found to have an anti-angiogenic effect on human skin cancer cells, and this effect was not shared by other antioxidants such as alpha-tocopherol.19
Why not just drink cranberry juice?
Next time you go to the grocery store, read the label on a bottle of cranberry juice and you’ll realize why. Most commercially produced cranberry juice is sweetened with high fructose corn syrup—enough to spike insulin levels and negatively impact your immune system. It also contains a lot of unnecessary calories, about 140 per 8 oz serving.
It’s possible to drink unsweetened cranberry juice, but you’d have to drink a lot of it, and it’s so sour it’s hard to get it down. In terms of cost, effectiveness, and taste; encapsulated cranberry extract is the preferred way to get the benefits that cranberry offers.
How safe is cranberry extract?
Very. It has not been reported to cause side effects and can be used safely during pregnancy and breastfeeding. Individuals with a history of kidney stones should consult a medical professional before using cranberry extract for long periods of time since there is some indication long-term use might increase the risk of developing a kidney stone.20
One capsule of concentrated cranberry extract (500 mg) can be taken twice a day. A typical recommended dose for UTIs prevention is 500-1,000 mg a day. For a preventative dosage, take 1 to 2 capsules per day. For treatment, take 3 to 6 capsules per day. Cranberry extract capsules can also be released in warm water and used as an oral rinse.
There is now a strong scientific basis for the use of cranberries to reduce the risk of E. coli adhesion to bladder cells and the onset of urinary tract infection. It’s interesting that science is also elucidating its historical use as a preventative against cancer. Undoubtedly with more research, we’ll soon have a clearer picture of the many ways in which cranberry extract can help treat and prevent other health problems that are caused by the adhesion of bacteria to surfaces such as the bladder and teeth.
- Presser, Arthur M. Pharmacists’ Guide to Medicinal Herbs. Petaluma, CA: Smart Publications, 2000, 109-112.
- Yan X, Murphy BT, Hammond GB, Vinson JA, Neto CC. Antioxidant activities and antitumor screening of extracts from cranberry fruit (Vaccinium macrocarpon). J Agric Food Chem.2002 Oct 9;50(21):5844-9.
- Kandil FE, Smith MA, Rogers RB, Pepin MF, Song LL, Pezzuto JM, Seigler DS. Composition of a chemopreventive proanthocyanidin-rich fraction from cranberry fruits responsible for the inhibition of 12-O-tetradecanoyl phorbol-13-acetate (TPA)-induced ornithine decarboxylase (ODC) activity. J Agric Food Chem. 2002 Feb 27;50(5):1063-9.
- Bomser J, Madhavi DL, Singletary K, Smith MA. In vitro anticancer activity of fruit extracts from Vaccinium species. Planta Med. 1996 Jun;62(3):212-6.
- Foxman, B. Am. J. Med. 2002; 113 (suppl. 1A), 5S.
- Duke, James A. The Green Pharmacy. St. Martin’s Press, New York, NY. 1997, 99-100.
- Anderson, G. et al. Intracellular Bacterial Biofilm-Like Pods in Urinary Tract Infections. Science Vol 301 4, July 2003.
- Howell AB. Cranberry proanthocyanidins and the maintenance of urinary tract health. Crit Rev Food Sci Nutr. 2002;42(3 Suppl):273-8.
- Azfriri D, et al. Inhibitory activity of cranberry juice on adherence of type 1 and type P fimbriated Escherichia coli to eucaryotic cells.Antimicrob Agents Chemother 1989;33:92-8.
- Avorn J, et al. Reduction of bacteriuria and pyuria after ingestion of cranberry juice. JAMA 1994;271:751-4.
- Walker EB, et al. Cranberry concentrate: UTI prophylaxis. J Fam Prac 1997;45:167-8.
- Stothers L. A randomized trial to evaluate effectiveness and cost effectiveness of naturopathic cranberry products as prophylaxis against urinary tract infection in women. Can J Urol. 2002 Jun;9(3):1558-62.
- Biering-Sorensen F. Urinary tract infection in individuals with spinal cord lesion. Curr Opin Urol. 2002 Jan;12(1):45-9.
- Yamanaka A, Kimizuka R, Kato T, Okuda K. Inhibitory effects of cranberry juice on attachment of oral streptococci and biofilm formation. Oral Microbiol Immunol. 2004 Jun;19(3):150-4.
- Weiss EL, Lev-Dor R, Sharon N, Ofek I. Inhibitory effect of a high-molecular-weight constituent of cranberry on adhesion of oral bacteria. Crit Rev Food Sci Nutr. 2002;42(3 Suppl):285-92.
- Murphy BT, et al. Identification of triterpene hydroxycinnamates with in vitro antitumor activity from whole cranberry fruit (Vaccinium macrocarpon). J Agric Food Chem . 2003 Jun 4;51(12):3541-5.
- Yan X, Murphy BT, Hammond GB, Vinson JA, Neto CC. Antioxidant activities and antitumor screening of extracts from cranberry fruit (Vaccinium macrocarpon). J Agric Food Chem. 2002 Oct 9;50(21):5844-9.
- Ferguson PJ, et al. A flavonoid fraction from cranberry extract inhibits proliferation of human tumor cell lines. J Nutr. 2004 Jun;134(6):1529-35.
- Roy S, Khanna S, Alessio HM, Vider J, Bagchi D, Bagchi M, Sen CK. Anti-angiogenic property of edible berries. Free Radic Res. 2002 Sep;36(9):1023-31.
- Terris MK, Issa MM, Tacker JR. Dietary supplementation with cranberry concentrate tablets may increase the risk of nephrolithiasis. Urology 2001;57:26-9.